The present invention relates to novel antitumor compounds.
DC-52 is an antibiotic represented by the following formula and has an antitumor activity against lymphocytic leukemia P388, etc. as well as an antibacterial activity against various bacteria (Japanese Published Unexamined Patent Application No. 170189/82). ##STR2##
Further, DX-52-1 which is a derivative of DC-52 and which is represented by the following formula is known to have an antitumor activity (Japanese Published Unexamined Patent Application No. 210086/84, which corresponds to U.S. Pat. No. 4,650,869, issued Mar. 17, 1987). ##STR3##
DC-52 derivatives which have more excellent antitumor activity are always in demand as well as other antitumor antibiotics.